ERG5 or Sterol 22-desaturase is a
cytochrome P450
Cytochromes P450 (P450s or CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that mostly, but not exclusively, function as monooxygenases. However, they are not omnipresent; for examp ...
enzyme
An enzyme () is a protein that acts as a biological catalyst by accelerating chemical reactions. The molecules upon which enzymes may act are called substrate (chemistry), substrates, and the enzyme converts the substrates into different mol ...
in the ergosterol biosynthesis pathway of
fungi
A fungus (: fungi , , , or ; or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and mold (fungus), molds, as well as the more familiar mushrooms. These organisms are classified as one ...
''
Saccharomyces cerevisiae
''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have be ...
'' (Baker's yeast, a model organism), with the CYP Symbol CYP61A1. CYP61A1 is one of only three P450 enzyme found in baker's yeast, the other two are
CYP51F1 and
CYP56A1
Cytochrome P450-DIT2 or CYP56A1 is one of the only three P450 enzyme found in fungi baker's yeast (''Saccharomyces cerevisiae''), the other two are CYP51F1(ERG11) and CYP61A1(ERG5) in the ergosterol biosynthesis pathway. CYP56A1 thought to cataly ...
. The ortholog in ''
Schizosaccharomyces pombe
''Schizosaccharomyces pombe'', also called "fission yeast", is a species of yeast used in traditional brewing and as a model organism in molecular and cell biology. It is a unicellular eukaryote, whose cells are rod-shaped. Cells typically meas ...
'' (fission yeast, the second sequenced
model fungi), was named CYP61A3 for historical reasons, and is only one of two P450 enzyme found with CYP51F1. ERG5 catalyzes the C22-C23 double bond formation on the sterol side chain of
ergostatrienol to convert it into
ergostatetraenol, then the C24 double bond of ergostatetrenol will be
hydrogenation
Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to redox, reduce or Saturated ...
reduced into
ergosterol
Ergosterol (ergosta-5,7,22-trien-3β-ol) is a mycosterol found in cell membranes of fungi and protozoa, serving many of the same functions that cholesterol serves in animal cells. Because many fungi and protozoa cannot survive without ergostero ...
by
ERG4.
Ortholog
Most fungi have only one CYP61 gene, and CYP61 global distributed in fungi.
There are some of the ortholog found in
early genome sequenced organism:
References
Cytochrome P450
EC 1.14.19
Saccharomyces cerevisiae genes
{{Enzyme-stub